The seat depth of a sofa (i.e. the distance from a backrest to a front edge of a sofa) desired by or suited for different people may vary because of difference in figure and seating angle of different individuals. Traditional sofas have a non-adjustable seat depth. People of large figure or petty figure may apparently feel uncomfortable when seating or reclining on the sofa with a non-adjustable seat depth.
Sofas with adjustable seat depth now have been seen in the market, but the seat depth of these sofas is usually adjusted in such a manner that the position of a backrest is adjusted to a preset position by tongue and groove engagement. The range of adjustable seat depth achieved by these sofas is very limited, and furthermore because of large size of the backrest, normally an average user may have difficulty in adjusting the position of the backrest. In addition, repeated dismounting or connection consequently may shorten life of these sofas.
Therefore, the present invention is intended to overcome one or more of the above defects.